what mods do you have now? the stock cams wont be giving you too much of a restricition if you just have basic mods as it is (which is probably the case if you're running stock ecu), its probably better to spend that money else where.
if you already have the basic catback and CIA setup, maybe go for some headers, or get you ecu "chipped" so it can be tuned, either of those options will give you better gains then dropping in some cams in an otherwise stock engine
also, i would also think of other areas besides just the engine to spend money on. If its a gts, try and source the gtst brakes which would give you much improved braking, or if your suspension is fairly stock get some upgraded springs/shocks or get a new adjustable coilover, or sway bars etc...
depending on how much you are willing to burn (yes burn because you wont get it back, its all fun though), cams probably isnt the best option